1. Field of the Invention
The present invention relates to a pulse combustion device, and more particularly to a pulse combustion device of the type which is supplied with a rich mixture of primary air and gaseous fuel and further supplied with secondary air to establish pulse combustion of the mixture therein.
2. Description of the Prior Art
As shown in FIG. 4, a conventional pulse combustion device of this kind comprises a housing 10 forming therein a combustion chamber 11, a spark plug SP mounted on the housing 10 and having an electrode located in the combustion chamber 11, an air intake valve plate 12 secured in place within the housing 10 to form an air intake chamber R, and a gas intake nozzle 13 coupled with the valve plate 12 to admit a rich mixture of primary air and gaseous fuel therethrough into the combustion chamber 11. The air intake chamber R is connected to an electrically operated blower B to be forcibly supplied with secondary air therefrom. The valve plate 12 is provided with air intake ports each controlled by a non-return valve V.sub.1. The gas intake nozzle 13 is provided with a gas intake controlled by a non-return valve V.sub.2. In such an arrangement of the pulse combustion device, a flame trap 14 is secured in place within the housing 10 at a position spaced from the valve plate 12 to prevent burning from taking place near the non-return valves V.sub.1 and V.sub.2. In activation of the pulse combustion device, moving parts such as the non-return valves V.sub.1, V.sub.2 occur unpleasant noises during pulse combustion of the mixture and are defaced inevitably, resulting in a trouble of the device in a short period of time. It is also difficult to partly control the pulse combustion in accordance with changes of a combustion load acting on the device.